Hence, wherever we meet with vital phenomena that present the two aspects, physical and psychical there naturally arises a question as to the relations in which these aspects stand to each other.

In the animal world, on the other hand, the process of evolution is characterised by the progressive discrimination of the animal and vegetative functions, and a consequent differentiation of these two great provinces into their separate departments.

In Aristotle the mind, regarded as the principle of life, divides into nutrition, sensation, and faculty of thought, corresponding to the inner most important stages in the succession of vital phenomena.

Wilhelm Wundt Quotes